Use of aromatase inhibitor forms basis of warning letter

A recently posted warning letter cites a New York company for the presence of an aromatase inhibitor in one of its dietary supplements. This class of chemicals is popular with strength trainers for its purported ability to suppress estrogen levels.

Muscle builders seeking the ultimate in shredded physiques have long focused on boosting testosterone levels as one way to get there. But limiting estrogen in the system has been seen as playing a role, too, as higher levels of this hormone have been associated with higher body fat levels.

In the warning letter, FDA cited a number of violations that caused the supplements packaged and shipped from the company’s facility in Hicksville, NY to be adulterated. Chief among these was the inclusion of an ingredient called Arimistane (Androsta-3,5-Diene-7,17-Dione) in a product meant to help depress estrogen levels.

“The ‘Arimistane' ingredient listed on your product label, Androsta-3,5-Diene-7,17-Dione, is an aromatase inhibitor and does not constitute a dietary ingredient under section 201(ff)(1) of the FD&C Act,”​ the agency wrote.

FDA rules ingredient is prescription drug

FDA claimed the company was making illegal disease type claims on the product, making it in effect a drug.

The agency also took the somewhat unusual step of ruling that it is a prescription drug, “[B]ecause of its toxicity or other potentiality for harmful effect, or the method of its use, or the collateral measures necessary to its use, it is not safe for use except under the supervision of a practitioner licensed by law to administer it. Adverse events associated with the use of FDA-approved aromatase inhibitors include the following: decreased rate of bone maturation and growth, decreased sperm production, infertility, aggressive behavior, adrenal insufficiency, kidney failure, and liver dysfunction.”​

Similar to legal ingredient

Androsta-3,5-Diene-7,17-Dione is chemically similar to 7-Keto DHEA, with some references listing as a metabolite. 7-Keto DHEA is legally on the market, with a successful NDI notification dating back to 1997​​ that was filed jointly by GNC and Humanetics.

Consumer demand plays role

Despite years of enforcement, adulterated sports supplements continue to appear in the market, and it’s an issue not confined to the US.

A recent study done on supplements in Greece found that about 10% of the supplements consumed by young, recreational athletes in that country contained anabolic steroids, prohormones, selective androgen receptor modulators (SARMs), and aromatase inhibitors

The authors of the study, which appeared in the journal Food and Chemical Toxicology​​​, said one reason these products continue to appear is that consumers actively seek them out.